This child tracking system is perfect for giving your child some freedom and giving you peace of mind. The child tracking system allows you, the parent, to set an adjustable boundary from 10 feet up to 300 feet. The parental unit will allow you to see how close the child is to the boundary. Audible alert if child goes outside of pre-set boundary. Panic button also provided for child. Each unit comes with a instructional DVD. Requires 4 AAA batteries that are not included.